Considerable evidence suggests that periodontitis, the major cause of tooth loss in the world, is initiated and perpetuated by members of the oral microflora. The long-term objective of this proposal is to assess the role of host attachment proteins, including fibronectin, fibrinogen and laminin as modulators of host colonization by suspected periodontal pathogens. These attachment proteins bind bacteria, host cells and a variety of ligands and may serves as "linker" molecules between bacteria and host tissue cells. Studies described are directed toward eludicating the nature of attachment protein-bacterial interactions. The kinetics and specificity of laminin binding to Bacteroides gingivalis (W) will be determined, including purification of the Bacteroides gingivalis (W) laminin receptor. Bacteroides gingivalis strains, other oral Bacteroides species and a variety of suspected periodontopathic bacteria will be assessed for the ability to bind fibronectin, fibrinogen and laminin. These survey studies will lead to purification and characterization of selected attachment protein receptors. Information relative to the nature of attachment protein-bacterial interaction may be critical to understanding colonization of the periodontal pocket by specific members of the indigenous oral microflora and may provide mechanisms for selectively interfering with such host colonization by pathogens.